The 112-year-old railroad bridge linking Boom Island and Nicollet Island has been closed to all but foot and bike traffic due to advanced deterioration of the bridge below the deck that was detected by a city inspection.

The closing of the 175-foot crossing to vehicles isn’t expected to have much public impact because the span is used mainly by maintenance vehicles of the Minneapolis Park and Recreation Board, which plow trails that run across the bridge.

The 1901 through-truss bridge is safe for individuals, the Park Board said in a news release. Jersey barriers have been placed at either end of the bridge to block vehicles.

The Life Time Fitness Commitment Day 5K race scheduled for Jan. 1 will use the bridge as planned, the Park Board said.

The bridge crosses the east channel of Nicollet Island, part of a corridor that extends down the east flank of the island’s north half to where the line once connected with Burlington Northern tracks.

The bridge was used by the Wisconsin Central Railroad as part of its rail yard, replacing lumberyards on Boom Island that were destroyed in an 1893 fire.

The rail yards were cleared in the 1970s in anticipation of the routing of Interstate 335 across Boom Island before opponents stalled that project. Roundhouse foundations are buried in the park that replaced the rails on Boom Island.

Earlier this week, Amazon announced that it's hiring 1,000 more full-time workers at its Shakopee fulfillment center. But city and county officials are still assessing reliable transportation options for the 1,500 people who already work there.